-LRB- CNN -RRB- -- It has been five years since Mohammad Z. left Syria to train as a doctor in Detroit .

He works long hours . He 's big on hockey . He 's devoted to the Red Wings .

He 's immersed in America , yet his heart is with Syria and the Syrian people .

It 's hell inside Syria . But for Mohammed and other Syrian expatriates who want to end the regime of Bashar al-Assad , this is a kind of golden moment . Ethnic and religious and political divisions are melting away to serve one shimmering goal .

`` I ca n't tell you how many wonderful Syrians I have met here who 've devoted their money and time to see a democratic , free Syria , '' said Mohammed , whose last name is being withheld by CNN to protect his brother and parents in Syria . `` You see the Christians , the Muslims , the nonreligious people ; you see people from different ethnic backgrounds : Arabic , Assyrian and Kurds . ''

An underground newspaper in Syria recently published an essay of Mohammad 's . In it , he wrote , `` The revolution has brought us together , and we had scattered in loneliness . ''

For Mohammad and many other Syrian expatriates , there is no going back to the old Syria . For them , Syria has to change .

`` These are people who 've been exposed to the American culture and brought up in an environment -- even in Syria -- where there was Internet and dishes and satellites and they can see how the rest of the world lives , '' said Naser Danan , a Cleveland-based doctor with the Syrian Expatriates Organization .

While the expat group has members in other Arab countries and in Europe , Danan estimated that a majority of the 600 or so members are young doctors in the United States -- ironic , because al-Assad himself has a medical degree .

The group supports an end to al-Assad 's regime , though it does n't act as a political opposition entity . Members raise money to buy food and medicine for Syrians caught in the violence , and they speak in public about what 's going on in Syria .

Cancer researcher Hazem Hallak recently spoke to a group of high-school students in Ardmore , Pennsylvania . When one of the students asked how he reacts to the latest videos coming out of Syria , Hallak said he does n't watch anymore .

He explained why by describing the last video he watched from Syria . Someone recorded Syrian soldiers invading a house looking for the husband of the household . When they did n't find him , Hallak said , they cut off the head of his young son , hung it in the doorway and told his wife , `` This is what will happen to your husband if he does n't turn himself in . ''

Last May , Hallak 's brother , a doctor in Syria , was arrested and killed -- his body mutilated -- after he returned from a trip to the United States .

A few expatriates in the United States are part of the Syrian National Council , the group that many Syrians consider to be the official political opposition .

One of them is George Netto , a cancer specialist who teaches and practices at Johns Hopkins University in Baltimore .

Netto , who is Christian by birth , said he joined the opposition group `` to show it 's really the entire spectrum of the Syrian people fighting the regime : Christian , Sunnis , poor , rich , educated and noneducated ... we wanted to burst that bubble they 're trying to depict that it 's only armed radicals or armed gangs . ''

In Detroit , Mohammad said he was going to anti-al-Assad rallies even before the Syrian secret police , the Mukhabarhat , arrested his brother who was protesting in Syria .

Mohammad said the police kept his brother locked up for three months . He said they interrogated him and tortured him from day one . -LRB- Listen to Mohammed read his brother 's essay about that time -RRB-

After three months , the police let Mohammed 's brother go to make room for a wave of new prisoners . But as soon as he was freed , he returned to protesting .

Mohammad said he would not tell his brother to stop protesting . If he were in Syria now , he said , he would do the same thing .

`` This is not only an uprising , '' he said . `` It 's an epic , a human epic that 's being written by the Syrian people . ''

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Syrian expatriates across the world are uniting against the regime of Bashar al-Assad

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Their mission is cutting across ethnic and religious lines

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Many Syrians are raising money in the U.S. and speaking about the crisis